The present invention is directed to a method by which a slub yarn may be formed from continuous filament yards.
Slub yarns are useful in providing novel effects for many areas of the textile industry. They are usually made by programmed overfeeds of two separate ends of flat filament yarn of any cross section to an intermingling device, such as a lofting jet, or by single or dual end feed to a random air jet process.
The Myers patent, U.S. Pat. No. 3,433,007, discloses one manner of forming a slub yarn. A continuous filament yarn is overfed continuously to the entrance of an aspirating jet device, and is also continously withdrawn from the entrance. The aspirating fluid stream in the jet device pulls the yarn into the jet device under tension, forms a loop in the yarn and entangles it. In this manner, the jet device forms random length and random thickness slubs at random intervals along the yarn.
The present invention is different from the Myers disclosure in that slubs are formed from individual filaments instead of the whole yarn. Also, the manner of forming the slubs is different.
The Shiranezawa et al patent, U.S. Pat. No. 3,312,052, discloses a different method from the Myers disclosure in that individual filaments of the continuous filament yarn are cut at various points along the length of the yarn to form free fiber ends, the free fiber ends then being entangled and interentangled to form slubs by passing the yarn into a fluid jet device having a turbulent fluid system. The yarn does not necessarily have to be overfed to the jet device so that slubs may be formed.
In the present invention, individual filaments are broken instead of being cut. The process disclosed thus also requires simpler apparatus to carry out the process than what would be required in the Shiranezawa et al disclosure.
Although the Williams et al patent, U.S. Pat. No. 3,007,298, teaches breaking filaments, such breaking is for a different purpose and results in a different effect. In Williams et al, a staple fiber yarn is produced from a continuous filament yarn. The continuous filament yarn is passed into a fluid jet in which the turbulence is increased to such extent so as to cause individual filaments to be torn and broken at intervals along their lengths as the filaments are whipped about in the turbulent fluid stream. The filaments are then drawn out of the turbulent stream at a speed lower than that at which they were fed to it. In addition to the turbulent stream of fluid breaking the filaments, loops, whorls, and convolutions are also formed in the filaments. The patent also teaches that the breakage may be facilitated by the interior of the jet device being formed with abrasive surfaces adapted to be engaged by the filaments as they are whipped about by the turbulent stream. The final or resulting product has an appearance somewhat like that of a spun yarn. There is no disclosure or suggestion of any slubs being formed from the broken filaments as in the manner disclosed in the present invention.
In the present invention, no loops, whorls or convolutions can be formed in the yarn bundle as in the Williams et al disclosure, because the yarn bundle is under drafting tension as it passes through the first fluid jet device. The fluid jet device also is operated under conditions to prevent such from being formed so as to prevent roll wraps on the drafting roll following the first fluid jet device.